We use R600 unleashed APs for dedicated wireless requirements during corporate events and have never seen a problem like this before. However saying this, I wouldn't recommend that you ran 400 users over just 3 APs. Although they are within scope, their throughput would be subject to a bottleneck experience.

I assume that they are all connected to the same VLAN and route traffic through a shared gateway? Are the APs connected at 1Gbps from the switch? Have you added a second LAG link per AP? Is there any rate limiting from the switches or APs?

400 is a pipe dream right now i would be happy to get to 200. all aps have a single 1Gbps link to the switch on their own VLAN. COuld you possibly explain more about this 2nd lag link ? this hasn't been brought up by ruckus support yet.

My understanding is the R710 is the only AP that supports LAG or LACP.

What are your channels set to?

Do you have any QoS in place i.e rate limiting in place?

"The backbone is all aps joined to there own 2500 series Aruba POE switch. Directly out a 100Mbit fibre connection." : So you have 3 PoE switches and each AP is connected to a different switch? How are those switches connecting to your core router? Are you daisy chaining them?

AP2, follow the same procedure but for 2.4G choose channel 6 and for 5G choose channel 161.

AP3, follow the same procedure but for 2.4G choose channel 11 and for 5G choose channel 165.

Since you have no QoS in place and most of your users are doing simple web browsing, I would rate limit them to 1Mbps up/down. You can do this at the router level or WLAN level, and since we are on the topic of Unleashed: WLAN>Advanced Options>Access Control>Rate Limit>Uplink: 1Mbps Downlink: 1Mbps.

Each AP is on its own VLAN correct? What is the subnet size? When the network becomes unusable, are clients spread out across the 3 AP's or is one being overloaded?

If you have 400 clients connected to a /24 IP subnet you are running out of addresses after 256 client connections. Maybe you can elaborate more on what happens when the network becomes "unusable"?

I may also recommend turning load balancing on, which will help spread clients between your access points: Go to Wi-Fi Networks > Edit > Show advanced options > Radio Control, and select the check box next to Load Balancing. Experiment with this option enabled and adjust accordingly.

At least one more AP to share client load would only be beneficial. I didn't read what Auth type on your WLAN?Simple WPA2/PSK may offer best performance over a Guest Access/HotSpot or 802.1x network, when roamingis involved. No benefit for R600 two Eth port to same switch (Link Aggregation), only 802.11ac Wave2 APs (R710,R610).

But can you see how much of your 100mb WAN pipe is in use? It may be the bottleneck for Internet browsing, as mentioned above.

No authentication open wireless, the internet does not appear to be a bottle neck the corporate network dosn't experience any slow down. I would like to avoid buying another access point as the customer is already fairly irritate this isn't working yet.

here's the latest response of what to do from ruckus, I haven't tried the suggestions mentioned here

Hi Matt,

I understand the issue still persists. Since we are not
able to troubleshoot the issue when the issue occurs live, kindly execute the
below commands from the Master APs CLI. The below commands will encourage the
clients to join with a higher data rate to the WiFi.

Please keep me posted on when the next event is
scheduled. It is important for us to see the issue live in order to identify
what is causing the issue. From the screenshots taken at the time of the event
shows that all the clients were connected with good speeds to the WLAN.